The bookstore application changed quite a bit in this chapter as we introduced DDD to the code. We have an application model now that better represents the domain where we do our business. We have also shifted our focus more onto entities and aggregates now, as we moved the core business logic into those classes as part of the refactor. Lastly, we removed that nasty cross-domain transaction, going with an event driven, two-part flow to handle inventory allocation for a sales order.

The changes we made here are important in the big picture of building a more scalable and flexible application. There's more to do though, and we'll start right in on some of those changes in the next chapter when we introduce event sourcing as a means of persistence. This is a big change to how and what you persist for an entity, so come with an open mind and get ready to rethink the way you handle persistent state.